| Photosensitizing porphyrin-triazine compound for bulk heterojunction solar cells | |
| Luechai A., Gasiorowski J., Petsom A., Neugebauer H., Sariciftci N.S., Thamyongkit P. | |
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| Abstract | |
| This report describes the synthesis of a novel porphyrin-triazine compound bearing three porphyrin macrocycles connected to each other via a triazine central unit, and investigation of its properties for possible use in bulk heterojunction solar cells (BHJ-SCs). The porphyrin macrocycles serve as light harvesting antennae, while the triazines have been widely known to be charge extracting promoters. According to cyclic voltammetric studies, the Highest Occupied Molecular Orbital (HOMO) and Lowest Unoccupied Molecular Orbital (LUMO) energy levels of the target compound were estimated to be at -5.4 and -3.5 eV versus vacuum, respectively. Photoluminescence measurements of the blended films of the porphyrin-triazine compound and phenyl-C 61-butyric acid methyl ester (PCBM) or poly(3-hexylthiophene) (P3HT) indicated that the charge transfer was possible when the target porphyrin was used as an electron donor together with PCBM as an acceptor. Additionally, the surface morphology of the films with different donor:acceptor ratios was investigated by atomic force microscopy (AFM). Upon variation of the donor:acceptor weight ratio and thickness of the organic layer, the short circuit current density (J SC) of the BHJ-SCs fabricated herein improved up to approximately 2.25 mA cm -2. © 2012 The Royal Society of Chemistry. | |
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| Blended films; Bulk heterojunction solar cells; Electron donors; Highest occupied molecular orbital; Light-harvesting; Lowest unoccupied molecular orbital; Macrocycles; Methyl esters; Organic layers; Photoluminescence measurements; Poly-3-hexylthiophene; Target compound; Voltammetric studies; Weight ratios; Atomic force microscopy; Charge transfer; Electron energy levels; Heterojunctions; Solar cells; Porphyrins | |
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| Synthesis of monodispersed polyisoprene-silica nanoparticles via differential microemulsion polymerization and mechanical properties of polyisoprene nanocomposite | |
| Kongsinlark A., Rempel G.L., Prasassarakich P. | |
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| Abstract | |
| Monodispersed polyisoprene-SiO 2 nanoparticles were successfully synthesized by a differential microemulsion polymerization of isoprene on silane treated nanosilica. Core-shell morphology was formed consisting of silica as the nano-core encapsulated by polyisoprene (PIP) as the nano-shell, as confirmed by TEM. PIP-SiO 2 nanoparticles were produced at 20-60nm with a narrow size distribution resulting in a reduced nano-SiO 2 aggregation in the PIP matrix. The influence of surfactant concentration, monomer/water ratio and SiO 2 loading on particle size, monomer conversion as well as grafting efficiency was investigated. The monomer conversion was 87% and the polymer grafting efficiency was as high as 78% at an extremely low surfactant concentration (3wt.% based on monomer). For rubber applications, the PIP-SiO 2 nanocomposite has been used as an effective nano-filler in natural rubber (NR) latex and the NR filled with PIP-SiO 2 prevulcanizate clearly showed an improvement in the storage modulus, tensile strength, tensile modulus, and anti-ageing properties. © 2012 Elsevier B.V. | |
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| Core-shell morphologies; Grafting efficiency; Microemulsion polymerization; Mono-dispersed; Monodispersions; Monomer conversions; Nano- SiO; Nano-silica; Nanofiller; Narrow size distributions; Polymer grafting; Surfactant concentrations; Elastic moduli; Grafting (chemical); Loading; Microemulsions; Monomers; Nanocomposites; Nanoparticles; Polyisoprenes; Polymerization; Rubber applications; Silica; Surface active agents; Synthesis (chemical) | |
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| Multilayer film assembled from charged derivatives of chitosan: Physical characteristics and biological responses | |
| Graisuwan W., Wiarachai O., Ananthanawat C., Puthong S., Soogarun S., Kiatkamjornwong S., Hoven V.P. | |
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| Polyelectrolyte multilayer films were successfully assembled from each of the three charged derivatives of chitosan; N-[(2-hydroxyl-3-trimethylammonium)propyl]chitosan chloride (HTACC), N-succinyl chitosan (SCC) and N-sulfofurfuryl chitosan (SFC), paired with one of the two oppositely charged polyelectrolytes, poly(acrylic acid) (PAA) and poly(allylamine hydrochloride) (PAH) on surface-treated poly(ethylene terephthalate) (treated PET) substrates by alternate layer-by-layer adsorption. Surface coverage and wettability of the multilayer films were determined by AFM and water contact angle measurements, respectively. Analysis by quartz crystal balance with dissipation (QCM-D) has suggested that all multilayer films are relatively rigid and have a high water content associated within their structures, accounting for up to 85-90% (w/w) for films having 7-10 layers. In vitro cytocompatibility tests for the fibroblast-like L929 cell line revealed a slight dependency for cell adhesion and proliferation on the outermost layer. The multilayer film containing HTACC exhibited moderate antibacterial activity against E. coli and S. aureus. Bearing negative charges, the multilayer films terminating with SFC and having at least 10 layers were capable of suppressing the adsorption of plasma proteins and platelet adhesion at a comparable level to the multilayer film assembled from heparin, a well-known antithrombogenic polymer. © 2012 Elsevier Inc. | |
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| AFM; Anti-bacterial activity; Anti-thrombogenicity; Biological response; Cell lines; Cytocompatibility; E. coli; High water content; In-vitro; Layer-by-layer adsorption; Layer-by-layers; Negative charge; Oppositely charged polyelectrolytes; Physical characteristics; Plasma protein; Platelet adhesion; Poly(allylamine hydrochloride); Polyacrylic acids; Polyelectrolyte multilayer film; Quartz crystal balances; S. aureus; Surface coverages; Water contact angle measurement; Adsorption; Carboxylic acids; Cell adhesion; Cell culture; Chitosan; Chlorine compounds; Escherichia coli; Polyelectrolytes; Polyethylene terephthalates; Polyethylenes; Quartz; Quartz crystal microbalances; Multilayer films; chitosan derivative; n [(2 hydroxyl 3 trimethylammonium)propyl]chitosan chloride; n succinyl chitosan; n sulfofurfuryl chitosan; plasma protein; polyacrylic acid; polyelectrolyte; unclassified drug; adsorption; antibacterial activity; article; atomic force microscopy; biocompatibility; biofilm; cell adhesion; cell proliferation; contact angle; Escherichia coli; fibroblast; in vitro study; nonhuman; priority journal; quartz crystal microbalance; Staphylococcus aureus; surface charge; surface property; thrombocyte adhesion; water content; wettability; Animals; Anti-Bacterial Agents; Anticoagulants; Biocompatible Materials; Cell Line; Chitosan; Escherichia coli; Escherichia coli Infections; Fibroblasts; Humans; Materials Testing; Mice; Staphylococcal Infections; Staphylococcus aureus; Surface Properties | |
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| Surface-quaternized chitosan particles as an alternative and effective organic antibacterial material | |
| Wiarachai O., Thongchul N., Kiatkamjornwong S., Hoven V.P. | |
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| Taking advantage of the large surface area that is covered with permanent positive charges of quaternary ammonium entities, this research aimed to develop environmentally friendly, organic antibacterial material from quaternized chitosan particles that may be applicable for biomedical devices, health and textile industries. The particles were formulated by ionic crosslinking of chitosan with tripolyphosphate followed by quaternization under heterogeneous conditions, via either direct methylation or reductive N-alkylation with a selected aldehyde followed by methylation. Sub-micron, spherical and positively charged quaternized chitosan particles were formed, as determined by 1H NMR, FT-IR, PCS and TEM analysis. Antibacterial activity tests, performed by viable cell (colony) counts, suggested that all quaternized chitosan particles exhibited superior antibacterial activity against the model Gram-positive bacteria, Staphylococcus aureus, as compared to the native chitosan particles at neutral pH. Only some quaternized chitosan particles, especially those having a high charge density and bearing large alkyl substituent groups, were capable of suppressing the growth of the model Gram-negative bacteria, Escherichia coli. The inhibitory efficiency of the quaternized chitosan particles was quantified in terms of the minimum inhibitory concentration (MIC). Damaging impact of the quaternized chitosan particles on the bacteria was also qualitatively determined by microscopic observation of the bacterial morphology. © 2011 Elsevier B.V. | |
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| Alkyl substituent; Anti-bacterial activity; Antibacterial materials; Bacterial morphology; Biomedical devices; Chitosan particles; Environmentally-friendly; Gram-negative bacteria; Gram-positive bacterium; Heterogeneous conditions; Ionic crosslinking; Large surface area; Microscopic observations; Minimum inhibitory concentration; N-alkylation; Neutral pH; Positive charges; Positively charged; Quaternary ammonium; Quaternization; Staphylococcus aureus; Submicron; TEM analysis; Tripolyphosphates; Viable cells; Aldehydes; Alkylation; Ammonium compounds; Bacteria; Escherichia coli; Methylation; Particles (particulate matter); Textile industry; Textile processing; Chitosan; benzaldehyde; chitosan; methyl iodide; propionaldehyde; quaternary ammonium derivative; tripolyphosphate; alkylation; antibacterial activity; article; bacterial count; bacterial viability; bacterium colony; biotechnological production; concentration (parameters); controlled study; cross linking; Escherichia coli; growth inhibition; infrared spectroscopy; methylation; microbial morphology; minimum inhibitory concentration; nonhuman; particle size; pH; photon correlation spectroscopy; priority journal; proton nuclear magnetic resonance; Staphylococcus aureus; transmission electron microscopy; Anti-Bacterial Agents; Chitosan; Escherichia coli; Magnetic Resonance Spectroscopy; Microbial Sensitivity Tests; Particle Size; Quaternary Ammonium Compounds; Spectroscopy, Fourier Transform Infrared; Staphylococcus aureus; Surface Properties; Bacteria (microorganisms); Escherichia coli; Negibacteria; Posibacteria; Staphylococcus aureus | |
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| Cl 3CCN/PPh 3 and CBr 4/PPh 3: Two efficient reagent systems for the preparation of N-heteroaromatic halides | |
| Kijrungphaiboon W., Chantarasriwong O., Chavasiri W. | |
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| Cl 3CCN/PPh 3 and CBr 4/PPh 3 are two highly reactive reagent systems for the conversion of N-heteroaromatic hydroxy compounds into N-heteroaromatic chlorides or bromides in moderate to excellent yields under mild and acid-free conditions. © 2011 Elsevier Ltd. All rights reserved. | |
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| bromide; chloride; halide; heterocyclic compound; heterocyclic hydroxy compound; article; chemical reaction | |
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| Cardanol-based bis(azo) dyes as a gasoline 91 colorant | |
| Paebumrung P., Petsom A., Thamyongkit P. | |
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| Novel bis(azo) dyes were successfully prepared from the coupling of either natural cardanol or its hydrogenated derivative with a series of diazotized aromatic amines and diamines. These new dyes were fully characterized by NMR, infrared and UV-visible spectroscopy and mass spectrometry. The dyes are highly soluble in a variety of common organic solvents and gasoline as a consequence of the cardanol unit. The physical properties of gasoline according to American Society for Testing and Materials standard were unaffected by the presence of the bis(azo) dye derived from 1-(4aminophenylazo)-2-naphthol at a concentration of 6 ppm and the dye showed excellent stability over a 3 month period. © AOCS 2011. | |
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| American society for testing and materials; Aromatic amines; Cardanols; Cashew nut shell liquid; CNSL; UV visible spectroscopy; Mass spectrometry; Materials testing; Organic solvents; Phenols; Ultraviolet visible spectroscopy; Gasoline; Anacardium occidentale | |
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| Mechanical and aging resistance performance of acrylic sheets containing EPDM-graft-poly (styrene-co-methyl methacrylate) | |
| Nuinu P., Pivsa-Art S., Hinchiranan N. | |
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| The addition of ethylene-propylene-diene rubber (EPDM) into acrylic sheets was expected to enhance their thermal and UV aging resistance for outdoor applications. According to the dissimilar polarity of EPDM and styrene (ST)/methyl methacrylate (MMA) monomer mixture (20/ 80% (w/w)) used for preparation of acrylic sheets, this research aimed to modify EPDM via graft copolymerization with ST and MMA to increase its compatibility. The graft copolymerization of ST and MMA at a ST/MMA ratio of 25/75% (w/w) onto EPDM was carried out in the solution polymerization initiated by benzoyl peroxide at 90 °C for 16 h, resulting in 88.1% grafting efficiency. The addition of 1.0-3.0% (w/w) of graft EPDM (GEPDM) into the acrylic sheets increased their impact strength (∼ 17-22%), but decreased their flexural strength (∼ 12-36%). However, their mechanical properties were improved after thermal and UV aging. Scanning electron microscopy (SEM) based analysis of the modified acrylic sheets revealed that the fracture surface shifted from brittle to ductile failure characteristics after modification. The thermogravimetric analysis results also exhibited that the addition of GEPDM improved the thermal and UV resistance of the modified acrylic sheets by increasing their initial decomposition temperature and activation energy of thermal decomposition. © 2012 Springer Science+Business Media B.V. | |
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| Acrylics; Activation analysis; Activation energy; Benzoyl peroxide; Copolymerization; Decomposition; Esters; Ethylene; Grafting (chemical); Impact strength; Mechanical properties; Rubber applications; Scanning electron microscopy; Styrene; Thermogravimetric analysis; Uranium metallography; Vanadium metallography; Aging properties; EPDM; Ethylene-propylene-diene rubbers; Graft co polymerizations; Grafting efficiency; Initial decomposition temperatures; Methyl methacrylates; Solution polymerization; Acrylic monomers | |
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